CN106162846A

CN106162846A - A kind of two users NOMA descending efficiency optimization method considering SIC energy consumption

Info

Publication number: CN106162846A
Application number: CN201610456836.1A
Authority: CN
Inventors: 张靖; 刘国亨; 张艳霞; 廖宴
Original assignee: Huazhong University of Science and Technology
Current assignee: Huazhong University of Science and Technology
Priority date: 2016-06-21
Filing date: 2016-06-21
Publication date: 2016-11-23
Anticipated expiration: 2036-06-21
Also published as: CN106162846B

Abstract

The invention discloses a two-user NOMA downlink energy efficiency optimization method considering SIC energy consumption. Firstly, the transmission power P of the base station, the channel condition H1 between user ₁ and the base station, and the channel condition between user 2 and the base station are obtained. H ₂ , and the signal voltage difference threshold θ for multiplexing signal separation required by the user receiver to perform SIC; users with better channel conditions perform SIC, and optimize the power allocation coefficient according to the channel conditions of users with better channel conditions, Obtain the optimal power distribution scheme; the present invention is applicable to the two-user NOMA downlink system that considers SIC energy consumption, compared with the two-user NOMA system that does not consider SIC energy consumption, while ensuring the total capacity of the system, better Improve the overall energy efficiency of the system.

Description

A Two-User NOMA Downlink Energy Efficiency Optimization Method Considering SIC Energy Consumption

技术领域technical field

本发明属于无线通信技术领域，更具体地，涉及一种考虑SIC能耗的两用户NOMA下行链路能效优化方法。The invention belongs to the technical field of wireless communication, and more specifically relates to a two-user NOMA downlink energy efficiency optimization method considering SIC energy consumption.

背景技术Background technique

面对流量需求的增长和频谱资源的匮乏，NOMA(Non-orthogonal MultipleAccess，非正交多址接入)技术作为一种功率域复用技术，以其在系统容量和频谱利用率的优势而成为下一代移动通信多址技术的热门候选之一。不同于4G系统中的频谱资源由一个用户单独占有，NOMA系统将同样的频谱资源分配给多个用户，并通过分配不同的功率系数来实现功率域复用。信道条件较好的用户通过执行SIC(Successive InterferenceCancellation，连续干扰消除)来消除来自其他用户的干扰，从而极大的增加系统的总容量。Facing the growth of traffic demand and the scarcity of spectrum resources, NOMA (Non-orthogonal Multiple Access, non-orthogonal multiple access) technology, as a power domain multiplexing technology, has become a One of the hot candidates for the next generation of mobile communication multiple access technology. Unlike the spectrum resources in the 4G system that are occupied by one user alone, the NOMA system allocates the same spectrum resources to multiple users, and realizes power domain multiplexing by allocating different power coefficients. Users with better channel conditions eliminate interference from other users by performing SIC (Successive Interference Cancellation, continuous interference cancellation), thereby greatly increasing the total capacity of the system.

节能减排、降低功耗的绿色通信作为下一代移动通信的要求需要进行NOMA系统能效优化的工作。传统的NOMA系统功率系数分配方案都是以系统总容量最大化为目标的，也缺少对于SIC信号处理部分能量消耗的考虑，因此按照传统的NOMA系统功率系数分配方案会使系统总能效较低。Energy saving, emission reduction, and green communication that reduce power consumption are the requirements of the next generation of mobile communication, and it is necessary to optimize the energy efficiency of the NOMA system. Traditional NOMA system power coefficient allocation schemes aim at maximizing the total system capacity, and lack of consideration for the energy consumption of SIC signal processing. Therefore, according to the traditional NOMA system power coefficient allocation scheme, the total system energy efficiency will be low.

发明内容Contents of the invention

针对现有技术的以上缺陷或改进需求，本发明提供了一种考虑SIC能耗的两用户NOMA下行链路能效优化方法，其目的在于在保障系统总吞吐量的情况下提升NOMA系统的能效。In view of the above defects or improvement needs of the prior art, the present invention provides a two-user NOMA downlink energy efficiency optimization method considering SIC energy consumption, the purpose of which is to improve the energy efficiency of the NOMA system while ensuring the total throughput of the system.

为实现上述目的，按照本发明的一个方面，提供了一种考虑SIC能耗的两用户NOMA下行链路能效优化方法，包括如下步骤：In order to achieve the above object, according to one aspect of the present invention, a kind of two-user NOMA downlink energy efficiency optimization method considering SIC energy consumption is provided, comprising the following steps:

(1)BS(Base Station，基站)更新当前网络的基本信息，并根据当前网络信息获取基站发射功率P、小区中执行NOMA通信的两个用户与基站之间的信道条件，以及用户接收机为执行SIC所需要进行复用信号分离的信号差门限阈值θ；(1) BS (Base Station, base station) updates the basic information of the current network, and obtains the transmit power P of the base station, the channel conditions between the two users performing NOMA communication in the cell and the base station according to the current network information, and the user receiver is The signal difference threshold θ required to perform multiplexing signal separation for SIC;

(2)根据两个用户中信道条件较好的用户的信道条件H₂、基站发射功率P以及所述信号差门限阈值θ确定能效最优的两个用户功率分配系数a₁和a₂；(2) Determine the power allocation coefficients a ₁ and a ₂ of the two users with the best energy efficiency according to the channel condition H ₂ of the user with better channel conditions among the two users, the base station transmit power P, and the signal difference threshold θ;

a₁是指两个用户中信道条件较差的用户的功率分配系数，a₂是两个用户中信道条件较好的用户的功率分配系数；a ₁ refers to the power allocation coefficient of the user with poorer channel conditions among the two users, and a ₂ is the power allocation coefficient of the user with better channel conditions among the two users;

(3)按照上述两个用户功率分配系数对两个用户进行功率分配，为信道条件较差的用户1分配a₁P，为信道条件较好的用户2分配a₂P，由此获得最大能效。(3) According to the above two user power allocation coefficients, power allocation is performed on the two users, and user 1 with poor channel conditions is allocated a ₁ P, and user 2 with good channel conditions is allocated a ₂ P, thereby obtaining the maximum energy efficiency .

优选地，上述考虑SIC能耗的两用户NOMA下行链路能效优化方法，其步骤(2)包括如下子步骤：Preferably, the above-mentioned two-user NOMA downlink energy efficiency optimization method considering SIC energy consumption, its step (2) includes the following sub-steps:

(2.1)比较两个用户的信道条件，确定信道条件好的用户为用户2，其信道条件为H₂；(2.1) compare the channel conditions of two users, determine that the user with good channel conditions is user 2, and its channel condition is H ₂ ;

(2.2)根据所述信道条件H₂、基站发射功率P以及信号差门限阈值θ确定能效最优的两个用户功率分配系数a₁和a₂；(2.2) Determine two user power allocation coefficients a ₁ and a ₂ with optimal energy efficiency according to the channel condition H ₂ , the base station transmit power P, and the signal difference threshold θ;

${a a}_{11} = = \frac{11}{22} + + \frac{11}{22} {[[{((\frac{\frac{22 θ θ}{P P} \cdot &Center Dot; ((ln ln ((\frac{{PH pH}_{22}}{n no})) - - 11))}{44}))}^{22} + + \frac{\frac{22 θ θ}{P P} \cdot &Center Dot; ((ln ln ((\frac{{PH pH}_{22}}{n no})) - - 11))}{22}]]}^{\frac{11}{22}} - - \frac{\frac{22 θ θ}{P P} \cdot &Center Dot; ((ln ln ((\frac{{PH pH}_{22}}{n no})) - - 11))}{88};;$

${a a}_{22} = = \frac{11}{22} - - \frac{11}{22} {[[{((\frac{\frac{22 θ θ}{P P} \cdot &Center Dot; ((ln ln ((\frac{{PH pH}_{22}}{n no})) - - 11))}{44}))}^{22} + + \frac{\frac{22 θ θ}{P P} \cdot &Center Dot; ((ln ln ((\frac{{PH pH}_{22}}{n no})) - - 11))}{22}]]}^{\frac{11}{22}} + + \frac{\frac{22 θ θ}{P P} \cdot &Center Dot; ((ln ln ((\frac{{PH pH}_{22}}{n no})) - - 11))}{88};;$

其中，n是指用户热噪声；a₁+a₂＝1。Wherein, n refers to user thermal noise; a ₁ +a ₂ =1.

优选地，上述考虑SIC能耗的两用户NOMA下行链路能效优化方法，其步骤(2.2)包括如下子步骤：Preferably, the above-mentioned two-user NOMA downlink energy efficiency optimization method considering SIC energy consumption, its step (2.2) includes the following sub-steps:

(2.2.1)基站同时对两个用户传输相互叠加的信号，(2.2.1) The base station transmits superimposed signals to two users at the same time,

用户1接收到的信号 The signal received by user 1

用户2接收到的信号 The signal received by user 2

其中，n₁为用户1的热噪声，n₂为用户2热噪声；n₁，n₂～CN(0，1)，n₁＝n₂＝n；其中，s₁为发送基站给用户1的信息，s₂为基站发送给用户2的信息；Among them, n ₁ is the thermal noise of user 1, n ₂ is the thermal noise of user 2; n ₁ , n ₂ ～CN(0,1), n ₁ =n ₂ =n; among them, s ₁ is the transmission base station to user 1 information, s ₂ is the information sent by the base station to user 2;

(2.2.2)由用户2执行SIC，先解码用户1的信息，将用户1的信息从相互叠加的信号中移除后再解码用户2自身的信息；(2.2.2) User 2 performs SIC, first decodes user 1's information, removes user 1's information from the superimposed signals, and then decodes user 2's own information;

由此，用户1不需要执行SIC，因而降低了用户1在SIC信号处理上的能耗；Therefore, user 1 does not need to perform SIC, thereby reducing the energy consumption of user 1 in SIC signal processing;

(2.2.3)获取用户2的中断概率 (2.2.3) Get the outage probability of user 2

在NOMA中，为了接收机顺利执行SIC，需满足a₁＞a₂，用户2有一定的中断概率；即两个用户功率分配系数差越大，用户2越容易执行SIC；两个用户功率分配系数差越小，用户2越难执行SIC，并有一定概率产生中断；In NOMA, in order for the receiver to perform SIC smoothly, a ₁ >a ₂ must be satisfied, and user 2 has a certain outage probability; that is, the greater the difference between the power allocation coefficients of two users, the easier it is for user 2 to perform SIC; the power allocation of two users The smaller the coefficient difference, the harder it is for user 2 to execute SIC, and there is a certain probability of interruption;

(2.2.4)获取两个用户的数据速率：(2.2.4) Get the data rate of two users:

${R R}_{11} = = {log log}_{22} ((\frac{{a a}_{11} {PH pH}_{11}^{22}}{{a a}_{22} {PH pH}_{11}^{22} + + {n no}_{11}} + + 11)),,$

${R R}_{22} = = {log log}_{22} ((\frac{{a a}_{22} {PH pH}_{22}^{22}}{{n no}_{22}} + + 11)) \cdot \cdot exp exp ((- - \frac{θ θ}{(({a a}_{11} - - {a a}_{22})) P P}));;$

其中，R₁是指用户1的数据速率，R₂是指用户2的数据速率；Among them, R1 refers to the data rate of user ₁ , and R2 refers to the data rate of user ₂ ;

(2.2.5)根据能效的定义，在考虑用户2的SIC电路能耗情况下，获取NOMA系统的能效方程 (2.2.5) According to the definition of energy efficiency, the energy efficiency equation of the NOMA system is obtained considering the energy consumption of the SIC circuit of user 2

其中P_SIC是指用户2接收机执行SIC所消耗的能量；Where _PSIC refers to the energy consumed by the user 2 receiver to perform SIC;

(2.2.6)根据a₁+a₂＝1，将能效方程变换成关于用户2的功率分配系数a₂的函数，(2.2.6) According to a ₁ +a ₂ =1, transform the energy efficiency equation into a function of the power distribution coefficient a ₂ of user 2,

${η η}_{E E. E E.} = = \frac{{log log}_{22} ((\frac{((11 - - {a a}_{22})) {PH pH}_{11}^{22}}{{a a}_{22} {PH pH}_{11}^{22} + + {n no}_{11}} + + 11)) + + {log log}_{22} ((\frac{{a a}_{22} {PH pH}_{22}^{22}}{{n no}_{22}} + + 11)) \cdot \cdot exp exp ((- - \frac{θ θ}{((11 - - 22 {a a}_{22})) P P}))}{P P + + {P P}_{S S I I C C}};;$

(2.2.7)通过使η_EE最大，对上述函数进行求导获得(2.2.7) By maximizing η _EE , deriving the above function to obtain

${a a}_{22} = = \frac{11}{22} - - \frac{11}{22} {[[{((\frac{\frac{22 θ θ}{P P} \cdot \cdot ((ln ln ((\frac{{PH pH}_{22}}{n no})) - - 11))}{44}))}^{22} + + \frac{\frac{22 θ θ}{P P} \cdot \cdot ((ln ln ((\frac{{PH pH}_{22}}{n no})) - - 11))}{22}]]}^{\frac{11}{22}} + + \frac{\frac{22 θ θ}{P P} \cdot &Center Dot; ((ln ln ((\frac{{PH pH}_{22}}{n no})) - - 11))}{88};;$

并进一步根据a₁+a₂＝1获得And further obtain according to a ₁ +a ₂ =1

${a a}_{11} = = \frac{11}{22} + + \frac{11}{22} {[[{((\frac{\frac{22 θ θ}{P P} \cdot \cdot ((ln ln ((\frac{{PH pH}_{22}}{n no})) - - 11))}{44}))}^{22} + + \frac{\frac{22 θ θ}{P P} \cdot \cdot ((ln ln ((\frac{{PH pH}_{22}}{n no})) - - 11))}{22}]]}^{\frac{11}{22}} - - \frac{\frac{22 θ θ}{P P} \cdot \cdot ((ln ln ((\frac{{PH pH}_{22}}{n no})) - - 11))}{88};;$

至此，两个用户的功率分配系数均已获得，BS按照以上功率分配系数对两个用户进行功率分配，即为用户1分配a₁P，为用户2分配a₂P即可获得最大能效。So far, the power allocation coefficients of the two users have been obtained, and the BS allocates power to the two users according to the above power allocation coefficients, that is, allocates a ₁ P to user 1 and a ₂ P to user 2 to obtain the maximum energy efficiency.

总体而言，通过本发明所构思的以上技术方案与现有技术相比，能够取得下列有益效果：Generally speaking, compared with the prior art, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

(1)本发明提供的考虑SIC能耗的两用户NOMA下行能效优化方法，为两个用户的功率分配提出了优化策略；用户在同一时隙或频域下对功率域进行复用，一个用户通信转变成两个用户通信，由于一个用户的信道条件很差，另一个用户对其产生的干扰不会过多地影响其性能，因此整个系统的吞吐量和用户总速率得到很大程度的提升，通过对能效方程求导又得到能效最优的功率分配系数，这样既保证了系统的总容量，又使能效最优，最大限度地减少能量消耗；(1) The two-user NOMA downlink energy efficiency optimization method considering SIC energy consumption provided by the present invention proposes an optimization strategy for the power allocation of two users; users multiplex the power domain under the same time slot or frequency domain, and one user The communication is transformed into two-user communication. Since the channel condition of one user is very poor, the interference caused by the other user will not affect its performance too much, so the throughput of the entire system and the total rate of users are greatly improved. , by deriving the energy efficiency equation and obtaining the power distribution coefficient with optimal energy efficiency, this not only ensures the total capacity of the system, but also optimizes energy efficiency and minimizes energy consumption;

(2)本发明提供的考虑SIC能耗的两用户NOMA下行能效优化方法，考虑了现实情况中执行SIC过程电路所消耗的能量，与不考虑SIC能耗的两用户NOMA下行链路系统相比，能够更加准确地描述系统所消耗的能量；(2) The two-user NOMA downlink energy efficiency optimization method that considers SIC energy consumption provided by the present invention considers the energy consumed by the implementation of the SIC process circuit in reality, compared with the two-user NOMA downlink system that does not consider SIC energy consumption , which can more accurately describe the energy consumed by the system;

在不考虑SIC能耗的NOMA下行链路系统中，认为所消耗的功率只有基站的发射功率，并认为系统能效是关于用户2功率分配系数a₂的单调增函数，即在a₂＝0.5，a₁＝0.5时系统能效取得最大值；但是，当两个用户的功率分配系数相等时，SIC电路将无法区分出两个信号，导致用户2的接收机无法对所接收的信号执行SIC，从而降低了系统的总传输容量，最终导致系统总能量效率的下降；In the NOMA downlink system that does not consider SIC energy consumption, it is considered that the power consumed is only the transmit power of the base station, and the system energy efficiency is considered to be a monotonically increasing function of the power allocation coefficient a ₂ of user 2, that is, at a ₂ =0.5, When a ₁ = 0.5, the energy efficiency of the system reaches the maximum value; however, when the power distribution coefficients of the two users are equal, the SIC circuit will not be able to distinguish the two signals, so that the receiver of user 2 cannot perform SIC on the received signal, thus The total transmission capacity of the system is reduced, which eventually leads to a decrease in the total energy efficiency of the system;

总体来说，本发明提出的以上技术方案与现有技术中不考虑SIC能耗的方法相比，在保证系统容量的基础上提高系统总能效，可提升整个网络的性能，既符合未来移动通信对频谱效率的要求，又符合绿色通信的趋势。Generally speaking, compared with the method in the prior art that does not consider SIC energy consumption, the above technical solution proposed by the present invention can improve the overall energy efficiency of the system on the basis of ensuring the system capacity, and can improve the performance of the entire network, which is in line with future mobile communication requirements. The requirement for spectrum efficiency is in line with the trend of green communication.

附图说明Description of drawings

图1是实施例中两用户NOMA下行链路系统模型示意图；Fig. 1 is a schematic diagram of a two-user NOMA downlink system model in an embodiment;

图2为本发明实施例提供的考虑SIC能耗的两用户NOMA下行能效优化方法的流程图；FIG. 2 is a flowchart of a two-user NOMA downlink energy efficiency optimization method considering SIC energy consumption provided by an embodiment of the present invention;

图3为实施例提供的能效优化方法与不考虑SIC能耗的两用户NOMA下行能效优化方法的系统总能效仿真对比图。Fig. 3 is a simulation comparison diagram of the total system energy efficiency between the energy efficiency optimization method provided by the embodiment and the two-user NOMA downlink energy efficiency optimization method without considering SIC energy consumption.

具体实施方式detailed description

为了使本发明的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本发明进行进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本发明，并不用于限定本发明。此外，下面所描述的本发明各个实施方式中所涉及到的技术特征只要彼此之间未构成冲突就可以相互组合。In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

本发明提供的考虑SIC能耗的两用户NOMA下行能效优化方案，根据信道条件好的用户的信息和基站的发射功率确定两个用户的功率分配系数，以达到能效最优的效果。The two-user NOMA downlink energy efficiency optimization scheme considering SIC energy consumption provided by the present invention determines the power allocation coefficient of the two users according to the information of users with good channel conditions and the transmission power of the base station, so as to achieve the effect of optimal energy efficiency.

图1所示，是实施例中两用户NOMA下行链路网络系统模型示意图；其中，信道条件差的用户为用户1，信道条件好的用户为用户2，用户2先通过执行SIC解码用户1的信息，并将其消除，再解码用户2的信息，以达到提高系统频谱效率的效果；实施例中，用户服从独立的泊松分布，根据泊松分布的特性，任何小区的几何特征都与其中一个小区一致，可将其中一个小区的分析结论扩展到蜂窝网络中的所有小区。As shown in FIG. 1 , it is a schematic diagram of a two-user NOMA downlink network system model in an embodiment; wherein, a user with poor channel conditions is user 1, and a user with good channel conditions is user 2, and user 2 first decodes user 1 by performing SIC information, and eliminate it, and then decode the information of user 2 to achieve the effect of improving the spectrum efficiency of the system; in the embodiment, the user obeys an independent Poisson distribution, and according to the characteristics of the Poisson distribution, the geometric characteristics of any cell are related to the One cell is consistent, and the analysis conclusion of one cell can be extended to all cells in the cellular network.

图2所示，是实施例供的考虑SIC能耗的两用户NOMA下行能效优化方法的流程图，具体包括如下步骤：As shown in FIG. 2 , it is a flow chart of the two-user NOMA downlink energy efficiency optimization method considering SIC energy consumption provided by the embodiment, which specifically includes the following steps:

(1)系统初始化，根据当前网络信息获取基站的发射功率P，小区中两个用户与基站之间的信道条件，以及用户接收机为执行SIC所需要进行复用信号分离的信号差门限阈值θ；实施例中用户接收机为执行SIC所需要进行复用信号分离的信号差门限阈值θ＝3mV；(1) System initialization, according to the current network information to obtain the transmit power P of the base station, the channel conditions between the two users in the cell and the base station, and the signal difference threshold θ for the multiplexing signal separation required by the user receiver to perform SIC ; In the embodiment, the signal difference threshold θ=3mV that the user receiver needs to perform multiplexing signal separation for performing SIC;

(2)比较两个用户的信道条件，信道条件差的用户1的信道条件用H₁表示，信道条件好的用户2的信道条件用H₂表示；由用户2执行SIC，先解码用户1的信息，将其移除后再解码自身的信息，用户1则不需要执行SIC；(2) Compare the channel conditions of two users. The channel condition of user 1 with poor channel condition is represented by H ₁ , and the channel condition of user 2 with good channel condition is represented by H ₂ ; user 2 performs SIC and first decodes user 1 information, remove it and then decode its own information, user 1 does not need to execute SIC;

根据用户2的信道条件H₂、基站发射功率P以及用户接收机为执行SIC所需要进行复用信号分离的信号差门限θ确定能效最优的两个用户的功率分配系数a₁和a₂，Determine the power allocation coefficients a ₁ and a ₂ of the two users with the best energy efficiency according to the channel condition H ₂ of user 2, the transmit power P of the base station, and the signal difference threshold θ for multiplexing signal separation required by the user receiver to perform SIC,

${a a}_{11} = = \frac{11}{22} + + \frac{11}{22} {[[{((\frac{\frac{22 θ θ}{P P} \cdot &Center Dot; ((ln ln ((\frac{{PH pH}_{22}}{n no})) - - 11))}{44}))}^{22} + + \frac{\frac{22 θ θ}{P P} \cdot &Center Dot; ((ln ln ((\frac{{PH pH}_{22}}{n no})) - - 11))}{22}]]}^{\frac{11}{22}} - - \frac{\frac{22 θ θ}{P P} \cdot &Center Dot; ((ln ln ((\frac{{PH pH}_{22}}{n no})) - - 11))}{88},,$

${a a}_{22} = = \frac{11}{22} - - \frac{11}{22} {[[{((\frac{\frac{22 θ θ}{P P} \cdot &Center Dot; ((ln ln ((\frac{{PH pH}_{22}}{n no})) - - 11))}{44}))}^{22} + + \frac{\frac{22 θ θ}{P P} \cdot &Center Dot; ((ln ln ((\frac{{PH pH}_{22}}{n no})) - - 11))}{22}]]}^{\frac{11}{22}} + + \frac{\frac{22 θ θ}{P P} \cdot \cdot ((ln ln ((\frac{{PH pH}_{22}}{n no})) - - 11))}{88};;$

(3)根据上述两个用户功率分配系数，基站为用户1分配a₁P的功率，为用户2分配a₂P；此时，系统的总能效η_EE取得最大值；在保证频谱效率的基础上，达到能效最优的有益效果。(3) According to the above two user power allocation coefficients, the base station allocates the power of a ₁ P for user 1 and a ₂ P for user 2; at this time, the total energy efficiency η _EE of the system reaches the maximum value; on the basis of ensuring spectral efficiency , to achieve the beneficial effect of optimal energy efficiency.

图3所示，是实施例提供的考虑SIC能耗的两用户NOMA下行系统总能效优化方法与不考虑SIC能耗的两用户下行系统总能效优化方法相比较，两者的能效仿真对比图；其中，参数为：用户接收机为执行SIC所需要进行复用信号分离的信号差门限阈值θ＝3mV，噪声n＝1×10^-14W，用户2执行SIC的电路所消耗能量P_SIC＝0.2W，用户1与基站之间的信道条件H₁＝-116.12dB，用户2与基站之间的信道条件H₂＝-107.95dB，不考虑SIC能耗的两用户下行系统总能效优化方法中a₂＝0.499。As shown in FIG. 3 , the total energy efficiency optimization method of the two-user NOMA downlink system considering the SIC energy consumption provided by the embodiment is compared with the total energy efficiency optimization method of the two-user downlink system that does not consider the SIC energy consumption, and the energy efficiency simulation comparison diagram of the two; Among them, the parameters are: the signal difference threshold θ=3mV for the multiplexing signal separation required by the user receiver to perform SIC, the noise n=1×10 ^-14 W, and the energy consumed by the circuit for user 2 to perform SIC P _SIC =0.2 W, the channel condition H ₁ =-116.12dB between user 1 and the base station, the channel condition H ₂ =-107.95dB between user 2 and the base station, in the total energy efficiency optimization method of the two-user downlink system without considering the SIC energy consumption a ₂ = 0.499.

从图3可以看出，对比于不考虑SIC能耗的两用户下行系统总能效优化方法，实施例提供的考虑SIC能耗的两用户下行系统总能效优化方法可提高整个网络的能效性能。It can be seen from FIG. 3 that, compared with the method for optimizing the total energy efficiency of the two-user downlink system that does not consider the energy consumption of the SIC, the method for optimizing the total energy efficiency of the two-user downlink system that considers the energy consumption of the SIC provided by the embodiment can improve the energy efficiency performance of the entire network.

本领域的技术人员容易理解，以上所述仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本发明的保护范围之内。It is easy for those skilled in the art to understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, All should be included within the protection scope of the present invention.

Claims

1. two users' NOMA downlink efficiency optimization method considering SIC energy consumption, it is characterised in that include walking as follows Rapid:

(1) obtain according to current network information base station transmitting power P, community perform NOMA communication two users and base station it Between channel condition, and receiver user is the signal difference threshold value θ performing to carry out required for SIC multiplexed signals separation；

(2) according to the channel condition H of the preferable user of channel condition in two users₂, described base station transmitting power P and described Signal difference threshold value θ determines two user power partition coefficient a that efficiency is optimum₁And a₂；

Wherein, a₁Refer to the power partition coefficient of the user that channel condition is poor, a in two users₂It it is channel bar in two users The power partition coefficient of the preferable user of part；

(3) according to said two user power partition coefficient, two users are carried out power distribution, for the use that channel condition is poor Family distribution a₁P, for channel condition, preferable user distributes a₂P, it is thus achieved that maximum efficiency.

2. two users' NOMA downlink efficiency optimization method as claimed in claim 1, it is characterised in that described step (2) Including following sub-step:

(2.1) compare the channel condition of two users, obtain the current channel condition H of the good user 2 of channel condition₂；

(2.2) according to described channel condition H₂, base station transmitting power P and signal difference threshold value θ determine that efficiency is optimum two User power partition coefficient a₁And a₂；

a_{1} = \frac{1}{2} + \frac{1}{2} {[{(\frac{\frac{2 θ}{P} \cdot (l n (\frac{{PH}_{2}}{n}) - 1)}{4})}^{2} + \frac{\frac{2 θ}{P} \cdot (l n (\frac{{PH}_{2}}{n}) - 1)}{2}]}^{\frac{1}{2}} - \frac{\frac{2 θ}{P} \cdot (l n (\frac{{PH}_{2}}{n}) - 1)}{8};

a_{2} = \frac{1}{2} - \frac{1}{2} {[{(\frac{\frac{2 θ}{P} \cdot (l n (\frac{{PH}_{2}}{n}) - 1)}{4})}^{2} + \frac{\frac{2 θ}{P} \cdot (l n (\frac{{PH}_{2}}{n}) - 1)}{2}]}^{\frac{1}{2}} + \frac{\frac{2 θ}{P} \cdot (l n (\frac{{PH}_{2}}{n}) - 1)}{8};

Wherein, n refers to user's thermal noise；a₁+a₂=1.

3. two users' NOMA downlink efficiency optimization method as claimed in claim 2, it is characterised in that described step (2.2) following sub-step is included:

(2.2.1) transmitted the signal being overlapped mutually to two users by base station simultaneously,

The signal that user 1 receives

The signal that user 2 receives

Wherein, n₁For the thermal noise of user 1, n₂For user 2 thermal noise；n₁,n₂～CN (0,1), n₁=n₂=n；Wherein, s₁For base Station is sent to the information of user 1, s₂The information of user 2 it is sent to for base station；

(2.2.2) performed SIC by user 2, first decode the information of user 1, the information of user 1 is moved from the signal being overlapped mutually Information except rear further decoding user 2 self；

(2.2.3) outage probability of user 2 is obtained

(2.2.4) data rate of two users is obtained:

R_{1} = \log_{2} (\frac{a_{1} {PH}_{1}^{2}}{a_{2} {PH}_{1}^{2} + n_{1}} + 1),

R_{2} = \log_{2} (\frac{a_{2} {PH}_{2}^{2}}{n_{2}} + 1) \cdot \exp (- \frac{θ}{(a_{1} - a_{2}) P});

Wherein, R₁Refer to the data rate of user 1, R₂Refer to the data rate of user 2；

(2.2.5) under the SIC circuit energy consumption considering user 2, the efficiency equation of NOMA system is obtained

Wherein P_SICRefer to that user 2 performs the energy that SIC is consumed；

(2.2.6) according to a₁+a₂=1, efficiency equation transform is become the power partition coefficient a about user 2₂Function,

η_{E E} = \frac{\log_{2} (\frac{(1 - a_{2}) {PH}_{1}^{2}}{a_{2} {PH}_{1}^{2} + n_{1}} + 1) + \log_{2} (\frac{a_{2} {PH}_{2}^{2}}{n_{2}} + 1) \cdot \exp (- \frac{θ}{(1 - 2 a_{2}) P})}{P + P_{S I C}};

(2.2.7) η is made_EEMaximum, carries out derivation acquisition to described function

a_{2} = \frac{1}{2} - \frac{1}{2} {[{(\frac{\frac{2 θ}{P} \cdot (l n (\frac{{PH}_{2}}{n}) - 1)}{4})}^{2} + \frac{\frac{2 θ}{P} \cdot (l n (\frac{{PH}_{2}}{n}) - 1)}{2}]}^{\frac{1}{2}} + \frac{\frac{2 θ}{P} \cdot (l n (\frac{{PH}_{2}}{n}) - 1)}{8};

And further according to a₁+a₂=1 obtains

a_{1} = \frac{1}{2} + \frac{1}{2} {[{(\frac{\frac{2 θ}{P} \cdot (l n (\frac{{PH}_{2}}{n}) - 1)}{4})}^{2} + \frac{\frac{2 θ}{P} \cdot (l n (\frac{{PH}_{2}}{n}) - 1)}{2}]}^{\frac{1}{2}} - \frac{\frac{2 θ}{P} \cdot (l n (\frac{{PH}_{2}}{n}) - 1)}{8} .